The apparatus and method of the invention are particularly appropriate for the separation of biological fluids comprising an aqueous component and one or more cellular components. For example, potential uses of the invention include: extracting a plasma component and a cellular component (including platelets, white blood cells, and red blood cells) from a volume of whole blood, the cellular component being subsequently filtered so as to remove platelets and white blood cells from the red blood cells; extracting a plasma component, in which a substantial amount of platelets is suspended, and a red blood cell component from a volume of whole blood, the white blood cells being subsequently removed by filtration from the platelet component and the red blood cell component; extracting a plasma component, a platelet component, and a red blood cell component from a volume of whole blood, the white blood cells being subsequently removed by filtration from the platelet component and the red blood cell component.
An apparatus for processing blood components is known from document WO 03/089027. This apparatus comprises a centrifuge adapted to cooperate with an annular separation bag connected to at least one product bag, e.g. a platelet component bag.
The centrifuge includes a rotor having a turntable for supporting the separation bag, and a central compartment for containing the product bag connected to the separation bag; and a squeezing system for squeezing the separation bag and causing the transfer of a separated component (e.g. platelets suspended in plasma) from the separation bag into the product bag.
With this apparatus, a single discrete volume of blood is processed at once.
An object of the present invention is to design a separation apparatus that can process at once at least two discrete volumes of a composite liquid, in particular discrete volumes that may or may not be the same, and with the proportions of the various components of the composite liquid that may vary from one discrete volume to another one. The object of the invention is further to maintain the centrifuge that is part of the separation apparatus in balance even when the discrete volumes and/or the components are not the same.
One aspect of the invention relates to a balancing assembly for a centrifuge having a rotor and more than one container on the rotor wherein each container is adapted to receive a composite fluid. The balancing assembly comprises a source of hydraulic liquid; a rotor duct in the rotor directly connected to the source of hydraulic liquid; an hydraulic chamber in each container on the rotor wherein the hydraulic chambers are interconnected and are connected to the rotor duct; a motor for rotating the rotor wherein rotation of the rotor causes hydraulic liquid to be transferred from the source to the interconnected hydraulic chambers to balance any unbalance in the rotor due to differences.
Another aspect of the invention relates to a method of balancing a centrifuge having a rotor and more than one containers on the rotor wherein each container contains a hydraulic chamber adapted to receive a composite fluid. The method comprises interconnecting the hydraulic chambers; rotating the rotor and the containers on the rotor; transferring a volume of hydraulic liquid into the interconnected hydraulic chambers comprising connecting a source of hydraulic liquid to the interconnected hydraulic chambers, and distributing by the rotation of the rotor the hydraulic liquid from the source to the interconnected hydraulic chambers.